A Russian court has sentenced an acclaimed Ukrainian film director to 20 years in a maximum-security prison on multiple terrorism charges.

The sentence was handed down after the North Caucasus District Military Court, located in the southern Russian city of Rostov-on-Don, on August 25 found Oleh Sentsov guilty of establishing a terrorist group, organization of two terrorist attacks and an attempted terrorist act, as well as an attempt to illegally acquire explosives.

Sentsov's co-defendant, 26-year-old Oleksandr Kolchenko, was found guilty of involvement with a terrorist group and sentenced to 10 years in prison.

After pronouncing the verdict and sentence, the judge asked the defendants if the court's ruling was clear to them.

In response, Sentsov and Kolchenko sang Ukraine's national anthem and chanted: "Glory to Ukraine! Glory to the Heroes!":

"Be strong, Oleh," Ukrainian President Petro Poroshenko wrote on his Facebook page. "There will come a time when those who organized this so-called trial will themselves sit on the bench of the accused."

Sentsov, who opposed Russia's March 2014 annexation of the Ukrainian peninsula, was arrested in May of that year on suspicion of planning the fire-bombings of pro-Russian organizations in Crimea.

The 39-year-old director denied all charges against him, saying they were politically motivated, and told the court on August 19 that a "trial by occupiers cannot be fair by definition."

The prosecution of Sentsov and Kolchenko has been widely criticized as retaliation for their outspoken opposition to Russia's annexation of Crimea.

The U.S. ambassador to Ukraine, Geoffrey Pyatt, described the sentences as "shameful" and condemned the "Russian farce of a 'legal process."

U.S. State Department spokesman John Kirby said the United States “strongly condemns” the sentencing of Sentsov and Kolchenko on “groundless allegations.” “This is clear miscarriage of justice,” the statement added.

EU foreign policy chief Federica Mogherini called on Russian authorities to "immediately release" Sentsov and Kolchenko and to guarantee their safe return to Ukraine.

“The EU considers the case to be in breach of international law and elementary standards of justice,” she said.

Heather McGill, Eurasia researcher at Amnesty International, said in a statement after the sentencing that "this whole trial was designed to send a message. It played into Russia’s propaganda war against Ukraine and was redolent of Stalinist-era show trials of dissidents."

McGill described the trial as "fatally flawed" and noted that allegations of torture and other ill-treatment alleged by Sentsov and a main witness were ignored by the court.

"Any testimony gained through torture and other ill-treatment must be thrown out, the 'terrorism' charges must be withdrawn, and Oleh Sentsov and Oleksandr Kolchenko should either be released or face a fair trial in a civilian court," McGill said.

Under international law, Russia as the occupying power in Crima is required to prosecute any defendents in civilian courts under Ukrainian law, according to the Amnesty International statement.

Sentsov and Kolchenko were arrested along with two other Ukrainian citizens -- Oleksiy Chyrniy and Hennadiy Afanasyev -- in May 2014.

Earlier, Chyrniy and Afanasyev had been found guilty of involvement in a terrorist cell and sentenced to seven years each in prison.

The latest appeal by the European Film Academy on August 19 included the signatures of 15 filmmakers, including Britain's Ken Loach and Germany's Wim Wenders, saying they were "deeply worried" by the prosecutions.

"We are shocked that the accusation of Oleh Sentsov having committed 'crimes of a terrorist nature' is still being upheld," the letter, addressed to Russian President Vladimir Putin, said.

"The prosecutors failed to provide any solid proof of the defendants' guilt," Kaplan told RFE/RL's Russian Service on August 24. "I think this trial is the beginning of serious repression in Russia. Current repressions are mild, but if they started talking about such long prison terms in Sentsov's case, the worst is ahead."

Kyiv and NATO have accused Russia of direct military intervention in Ukraine, where fighting between Ukrainian forces and pro-Russian separatists has killed more than 6,400 people since April 2014.

With reporting by TASS

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